Female estrogen is an important sex hormone secreted by female ovaries, which can promote the development and maturation of female sex organs, the development of female secondary sexual characteristics, and the maintenance of normal menstruation as well as reproductive functions. The causes of low female estrogen are as follows: 1. abnormalities in the hypothalamic-pituitary-ovarian axis, resulting in a decrease in ovarian secretion of estrogen and lower estrogen levels. 2. affected by diseases, such as diabetes, abnormal thyroid function and ovarian cysts, which can cause lower estrogen. 3. bad lifestyle habits, such as dieting and weight loss, staying up late, irregular lifestyle and excessive stress in life, which can cause lower estrogen levels. 4. Ageing, the ovarian function decreases during menopause and the level of secreted sex hormones is insufficient, which can cause the estrogen level to decrease.